GLENDALE, Ariz. — Dodgers pitcher Hyun-Jin Ryu threw 20 fastballs off a mound today, a small but noteworthy step forward in his shoulder rehab program.

“It was very good,” Ryu said through an interpreter. “It wasn’t all about the speed. It was more about location and how I felt.”

Ryu, who missed all of last season because of shoulder labrum surgery, had been limited to throwing from flat ground the last couple weeks. The left-hander still believes he can return to game action by May.

Why only fastballs Monday? Ryu said that his changeup and curveball don’t cause him any shoulder pain, but the 20-fastball session was simply the next step in his progression. His next date off a mound is to be determined.